I setup a subdomain to test something I’m working on and I used _test as the subdomain. The site would load but I kept getting odd errors when trying to login that I normally wouldn’t get if the login credentials were wrong. After looking into this more I found that the underscore prefix is what’s causing the problem which I found odd since both IIS and GoDaddy both allowed me to enter them without error.
IE9 & IE10 will show the page but won’t send cookies back to the server on POST. I’m not sure if there’s anything else it’s not doing but that’s the main thing I’m seeing.
FireFox, Opera, and Safari all work as intended and I can browse the site and login to it. Presumably these all work without any quirks as IE is.
Chrome doesn’t load the site at all and instead it redirects me to a Google search.
Since there’s three different outcomes here does anyone know what the correct outcome of this should be? According to this question my subdomain should be valid and work meaning Chrome and IE both have bugs.
I know underscore prefixed subdomains work on some level because at work I’m running the JetBrains License Server and have a TXT record called _jetbrains-license-server that’s been working fine for a couple years now.
Hostnames in the context of
AorAAAArecords can’t have an underscore. HoweverTXTrecords can contain the underscore (see here for a detailed discussion).